1. Field of the Invention
The present invention relates to a caster; and more particularly to a caster with a brake structure.
2. Description of the Prior Art
Casters are normally installed on various machines, cabinets, platforms or even nursing beds, and etc in order to make them to move smoothly and conveniently. When those apparatuses installed with the casters reach a desired position, the casters should be braked and stopped from rotation. Hence, many braking technologies for caster were developed on the market and generally include two types: one is the technology that employs an anti-slip block to press against the wheel on the caster to stop the caster by friction, such as: Taiwan Patent No. 096219293, entitled “brake structure for a caster”, and the other is the technology that engages a positioning element into the wheel to brake and stop the rotation the caster, such as Taiwan Patent No. 096218417, entitled “brake device for a caster” discloses engaging a positioning block into a groove in an inner side of the wheel to stop the caster, and Taiwan Patent No. 093210074, entitled “caster brake structure”, discloses inserting a pin into a through hole in the caster to stop the caster.
Although the above two common braking technologies for caster can stop the rotation of the caster, but they suffer from their respective problems. As for the technology that employs an anti-slip block to press the wheel to stop the caster, the braking force depends on the friction, so if an external force is greater than the static friction applied to the wheel by the anti-slip block, the wheel can rotate, thus losing the braking function. Especially, after a long time of use and abrasion, the static friction between the anti-slip block and the wheel will eventually become much smaller. Therefore, it is more difficult to stop the caster at the desired position.
In addition, as for the technology that engages a positioning element into the wheel to stop the caster, in order to make it easier and smoother for the positioning element to engage into the caster, a portion of the caster to be engaged with the positioning element is sized a little greater than the positioning element, so that even if the positioning element is engaged into the caster, the caster can still swivel slightly, thus providing a poor braking effect.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.